Ultrasonic imaging of layered structures utilizing nondestructive subnanosecond photoacoustic pulse generation

Abstract

We describe a photoacoustic ultrasonic imaging system that can provide separate acoustic information on a thick substrate and a thin coating simultaneously. This is achieved by generating an ultranarrow longitudinal pulse on the opaque layered sample, and detecting the series of substrate and coating echoes in high time resolution. The echo times, attenuations, and acoustic dispersions in each series provide information on the substrate or coating separately. New photoacoustic images of coatings and of substrates for coated ceramic substrates are presented.

Transdermal delivery of two antioxidants from different cosmetic formulations

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Laser excitation of ultrashort acoustic pulses: New possibilities in solid-state spectroscopy, diagnostics of fast processes, and nonlinear acoustics

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Photoacoustic Evaluation of Green State Alumina Samples

“…These short pulses have been used in various NDE applications involving coatings and the detection of cracks in bulk materials [2,3,4]. The generation efficiencies are fairly high, up to 30% when the laser pulse causes material ablation, therefore easy detection of the acoustic pulse is insured even through highly attenuating materials such as nonsintered ceramics.…”